Guide catheters and introducer sheaths are used in surgical applications to provide a passageway through which medical devices and/or therapeutic agents may be introduced within the body of a patient. In intravascular and coronary applications, such medical devices may include balloon dilation catheters, guide wires and other therapeutic devices, and the therapeutic agents typically include contrast media or other therapeutic fluids.
Guide catheters and introducer sheaths have a composite construction that includes a hollow shaft defined by an inner tube through which the medical devices or agents are delivered once the shaft has been inserted into the body of the patient. The inner tube typically comprises a lubricious material such as polytetrafluoroethylene (PTFE), commonly known as teflon. A reinforcement, such as a metal braid or coil surrounds the inner tube in order to provide kink resistance and torqueability, while retaining flexibility of the overall guide catheter or introducer sheath. An outer tube is typically formed from a polyether-block amide material marketed under the Trademark PEBAX or another equivalent material that is often applied via a shrink wrap process. Guide catheters and introducer sheaths are typically manufactured in a batch process utilizing precut lengths of PTFE tubing, as PTFE is known to be difficult to manage relative to standard thermoplastics in a continuous non-batch extrusion type process. The precut lengths of PTFE tubes are made kink resistant by applying a metal reinforcement, such as a coil or braid, around that fixed length of PTFE tubing. Next, an outer shrink wrap tube is slid over the sub-assembly. This assembly has been heated to activate the shrink tubing and mount the same onto the outer surface of the reinforcement and PTFE inner tube. The use of shrink tubing may add significant material costs to guide catheters and introducer sheaths. In addition, the labor and tooling required to manufacture guide catheters and introducer sheaths in a batch process can be significant.
A simple extrusion process for the inner tube using readily available thermoplastic materials, such as nylon, may appear at first glance to be a low cost alternative to the PTFE batch process currently used. However, thermoplastics tend to present a substantially higher co-efficient of friction than that associated with PTFE. Thus, common thermoplastics are generally not considered suitable for defining the inner lumen of guide catheters and introducer sheaths that must allow other devices to be easily slid through the inner lumen to remote locations within a patient being treated.
The present disclosure is directed toward one or more of the problems set forth above.